What should I be looking for to cure or lessen it?

Got HT out last night and after thinking the front Shimano LX brake been faultless for years, I notice it was juddering quite badly, enough that the forks were visibly flexing quite a lot.

Off-hand the disc looks straight & the caliper again looks centred on the disc fine. Is the fault exaggerated by the cheap and cheerful QR Tora’s?

I had this recently and it was the saw blade shaped rotor that was the issue, it was so bad that I had to have all the bushes changed… The judder was still happening so swapped for an original formula disc which has a rounder overall shape, and its all good now.

I have a spare disc I can drop on to try with out much bother, so can try that, but it’s currently got a matching (normal) shimano disc.

I have no other pearls I’m afraid… mine was crappy superstar job.

no worries, cheers for the reply.. a quick browse through the archives suggests checking the headset, fork wear (bushing), wheel bearings and the disc.. so I’ve something to be going on with.

Also check the caliper is done up tightly as mine had come loose and I thought the fork bushes must need replacing.

all food for thought… thanks.

give the disc a good clean.

Check that you’re not an alcoholic and have inadvertently forgotten to have your first Special Brew of the day.

There lots of things I am, an alcoholic ain’t one of them, it was more the worrying way the forks flexed that disturbed me about the whole thing.

Take this logically,easiest first.Check the headset is tensioned correctly,clean the disc,check the caliper alignment.If no improvement,check the disc is flat and straight,check the disc bolts are torqued up properly,and if this doesn’t help,it may start to become expensive.
Ian

passtherizla – Member
I had this recently and it was the saw blade shaped rotor that was the issue, it was so bad that I had to have all the bushes changed… The judder was still happening so swapped for an original formula disc which has a rounder overall shape, and its all good now

This ^

I bought a bigger formula rotor with teeth and had the same problem as you. Swapped back to my stock formula rotors and it magically disappeared

New wheel bearings and tightening the headset (both unnoticed otherwise), has cured the problem to the point that I didn’t feel it at all on the last ride (it might still be occuring to a lesser extent), a complete turn around

Cheers for your help & suggestions.